Rapid radiative clearing of protoplanetary discs
File(s)
Accepted version
Author(s)
Haworth, Thomas J
Clarke, Cathie J
Owen, James E
Type
Journal Article
Abstract
The lack of observed transition discs with inner gas holes of radii greater than ∼50 au implies that protoplanetary discs dispersed from the inside out must remove gas from the outer regions rapidly. We investigate the role of photoevaporation in the final clearing of gas from low mass discs with inner holes. In particular, we study the so-called ‘thermal sweeping’ mechanism which results in rapid clearing of the disc. Thermal sweeping was originally thought to arise when the radial and vertical pressure scalelengths at the X-ray heated inner edge of the disc match. We demonstrate that this criterion is not fundamental. Rather, thermal sweeping occurs when the pressure maximum at the inner edge of the dust heated disc falls below the maximum possible pressure of X-ray heated gas (which depends on the local X-ray flux). We derive new critical peak volume and surface density estimates for rapid radiative clearing which, in general, result in rapid dispersal happening less readily than in previous estimates. This less efficient clearing of discs by X-ray driven thermal sweeping leaves open the issue of what mechanism (e.g. far-ultraviolet heating) can clear gas from the outer disc sufficiently quickly to explain the non-detection of cold gas around weak line T Tauri stars.
Date Issued
2016-04-01
Date Acceptance
2015-12-29
Citation
Monthly Notices of the Royal Astronomical Society, 2016, 457 (2), pp.1905-1915
ISSN
0035-8711
Publisher
Oxford University Press
Start Page
1905
End Page
1915
Journal / Book Title
Monthly Notices of the Royal Astronomical Society
Volume
457
Issue
2
Copyright Statement
Copyright © 2016 Oxford University Press. This is a pre-copy-editing, author-produced version of an article accepted for publication in Monthly Notices of the Royal Astronomical Society following peer review. The definitive publisher-authenticated version Thomas J. Haworth, Cathie J. Clarke, James E. Owen, Rapid radiative clearing of protoplanetary discs, Monthly Notices of the Royal Astronomical Society, Volume 457, Issue 2, 01 April 2016, Pages 1905–1915, is available online at: https://doi.org/10.1093/mnras/stv3016
Identifier
http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:000373580500063&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=1ba7043ffcc86c417c072aa74d649202
Subjects
Astronomy & Astrophysics
CIRCUMSTELLAR DISKS
circumstellar matter
D-TYPE EXPANSION
EVOLUTION
GIANT PLANETS
H-II REGIONS
HYDRODYNAMIC MODELS
instabilities
PHOTOEVAPORATION
Physical Sciences
protoplanetary discs
Science & Technology
STAR-FORMATION
stars: pre-main-sequence
TRANSITION DISKS
X-RAY
X-rays: stars
Publication Status
Published
Date Publish Online
2016-02-05